The paper studies the changes concerning the ethnic structure of post-socialist Hungary. Based on the data of the 2011 census, the number of the non-Hungarian population has significantly increased between 2001 and 2011 and so has had the number of those who refused to answer. Behind this phenomenon several reasons can be identified, like the methodical changes in the data collection of the census, migration and subjective factors. Regarding the methodology, double identification in three ethnic categories was allowed in the last census, which resulted in the growing number of respondents who claimed both Hungarian and minority identity. Meanwhile, migration (including cross-border residential mobility) from Romania, Ukraine, Serbia and Slovakia has changed the ethnic landscape. Beyond the above factors, subjective factors have also contributed in the changes. The present paper argues that the self-identification of some minority groups is related to the symbolic ethnicity and the double and hybrid identities, thus the results of the census cannot be interpreted merely by the assimilationist approach.